/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *    https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.bigtop.manager.stack.core.spi;

import lombok.extern.slf4j.Slf4j;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.ServiceLoader;

@Slf4j
public class PrioritySPIFactory<T extends PrioritySPI> {

    private final Map<String, T> map = new HashMap<>();

    public PrioritySPIFactory(Class<T> spiClass) {
        for (T t : ServiceLoader.load(spiClass)) {
            if (map.containsKey(t.getName())) {
                resolveConflict(t);
            } else {
                map.put(t.getName(), t);
            }
        }
    }

    public Map<String, T> getSPIMap() {
        return Collections.unmodifiableMap(map);
    }

    private void resolveConflict(T newSPI) {
        T oldSPI = map.get(newSPI.getName());

        if (newSPI.compareTo(oldSPI.getPriority()) == 0) {
            throw new IllegalArgumentException(String.format(
                    "These two spi plugins has conflict identify name with the same priority: %s, %s", oldSPI, newSPI));
        } else if (newSPI.compareTo(oldSPI.getPriority()) > 0) {
            log.info("The {} plugin has high priority, will override {}", newSPI, oldSPI);
            map.put(newSPI.getName(), newSPI);
        } else {
            log.info("The low plugin {} will be skipped", newSPI);
        }
    }
}
